1. Field of the Invention
The invention relates to a projection apparatus having an illumination apparatus, and more particularly, to an illumination apparatus using a light beam to excite a phosphor layer so as to advance the luminance performance thereof and a projection apparatus using the same.
2. Description of Related Art
In order to solve the difficult issue that the light-emitting diode (LED) luminance is limited due to insufficient light-emitting efficiency thereof in a conventional optical architecture where a solid-state light emitting component, i.e., an LED, serves as the light source thereof, currently, a mixed light source using a laser diode (LD) and an LED was gradually developed. In the optical architecture of the mixed light source, blue light or ultraviolet laser light serves as a light source and the light beam is guided by a dichroic mirror to be normally incident upon a phosphor substance, for example, a green phosphor, so as to make the material to emit excited green phosphor light. At the time, the green phosphor light can serve as the green light source in the projection illumination. After that, the green phosphor light is guided again by the dichroic mirror and then blended with red light and blue light to finally form a white light source.
In the architecture of a mixed light source with an LD and an LED however, the problem of insufficient light conversion efficiency and insufficient light collection is still persisted. Such problem includes, for example, the light beam of the laser light source excites the phosphor substance one time only.
U.S. Pat. No. 7,070,300 discloses an illumination apparatus, where the illumination light source is LED and the light ray emitted by the light source gets a smaller divergence angle by means of the reflection layer on a beam-bunching device, so that the light beam can be more concentrative and emitted to a dichroic mirror. Thereafter, the light beam is reflected by a reflection mirror to a wavelength conversion component and a radiance enhancement structure. At the time, the light beam enters the beam-bunching device, and a portion of the light beam would be reflected by the reflection layer on the beam-bunching device so that the angle of incidence thereof for being incident upon the wavelength conversion component and the radiance enhancement structure gets smaller. Then, the light beam arrives at the wavelength conversion component through the radiance enhancement structure. When the light beam strikes onto the wavelength conversion component, an excited light beam is produced, wherein the excited light beam can penetrate the dichroic mirror and the light beam can be transmitted to a radiance enhancement film and a polarization component.
In U.S. Pat. No. 7,040,774, a light-recycling structure is disclosed, the structure includes an LED light source, a fluorescent layer, a reflection layer and an aperture. The phosphor substance in the reflection layer is distributed in spots and the rest is transparent material. When the light emitted by the LED penetrates the phosphor layer and gets a first time reflection by a reflection layer, the reflected light would get a second time reflection to arrive at the aperture. Moreover, when the light is emitted to the phosphor layer, the light is converted into light belonging to a second wavelength range, the light belonging to a second wavelength range is reflected to arrive at the aperture. At the time, the emitted light is a combined light including light belonging to a first wavelength range without conversion and the above-mentioned converted light belonging to a second wavelength range.